The **MAH28FAG-R** is a specific model of a **Brushless DC (BLDC) Cooling Fan**, typically manufactured by companies like **Nidec** or similar high-end thermal solution providers. These fans are engineered for high-performance cooling in servers, networking equipment, and industrial power supplies. --- ### 1. Technical Specifications The following table outlines the typical electrical and mechanical characteristics for this series: | Parameter | Specification (Typical) | | :--- | :--- | | **Rated Voltage** | 12V DC | | **Operating Voltage Range** | 7.0V – 13.8V | | **Rated Current** | ~0.30A - 0.60A (Varies by sub-revision) | | **Bearing Type** | Dual Ball Bearing (High Reliability) | | **Speed (RPM)** | High Speed (approx. 5,000 - 8,000 RPM) | | **Connector** | 3-pin or 4-pin (PWM) | | **Frame Material** | PBT Plastic (UL94V-0 Rated) | --- ### 2. Key Electronic Components & Features The MAH28FAG-R is more than just a motor; it contains an integrated circuit (IC) board that manages several electronic functions: #### A. Brushless DC Motor Controller Inside the hub, there is a **Hall Effect Sensor** and a driver IC. * **Function:** The sensor detects the magnetic position of the rotor. * **Action:** The IC switches the current through the stator coils at the exact right moment to maintain rotation without the friction of physical brushes. #### B. PWM Control (Pulse Width Modulation) If the model features a 4-wire interface, it includes a PWM control circuit. * **Function:** Allows the motherboard or system controller to adjust the fan speed dynamically. * **Benefit:** Reduces noise and power consumption when the system is idling. #### C. Tachometer (Frequency Generator) Output The "FG" or "R" suffix often indicates a **Speed Signal** output. * **Mechanism:** The fan outputs a square wave pulse (usually 2 pulses per revolution). * **Purpose:** Allows the system to monitor the fan's RPM and trigger an alarm if the fan stalls or fails. #### D. Protection Circuitry The internal PCB typically includes: * **Auto-Restart Protection:** If the blades are physically blocked, the IC cuts power to prevent the coils from burning out, then periodically attempts to restart. * **Reverse Polarity Protection:** Prevents damage if the positive and negative wires are accidentally swapped. --- ### 3. Pinout Configuration Standard wiring for this type of electronic part usually follows this color code: 1. **Black:** Ground (GND) 2. **Red:** Power (+12V) 3. **Yellow/White:** Tachometer (Speed signal) 4. **Blue (if 4-pin):** PWM Control signal ---